Semiconductor devices are used in a large number of applications including computers, mobile phones and most other electronic devices. For example, transistors can be used as switching devices to implement logic circuits. One of the goals in designing such transistors is to make the individual devices small, fast and power efficient. These goals are especially important in mobile applications where users want to be able to carry devices that implement a large number of tasks and use as little of the battery as possible.
One type of semiconductor device is a power transistor. A power transistor is designed to be able to carry relatively large amounts of current without being damaged. Such devices are typically larger than the logic transistors used to implement processor circuits but are able to withstand power levels that would harm the smaller devices. For example, a power transistor may be used to drive an electric device such as a DC motor.
One type of power transistor is a laterally diffused metal oxide semiconductor (LDMOS) transistor. LDMOS transistors can be used in a number of applications such as in RF/microwave power amplifiers, e.g., for base-stations that require high output power. Accordingly, LDMOS technology is effectively the dominant device technology used in high power RF amplifiers for frequencies ranging from 700 MHz to 3.8 GHz.